The efficacy of combined diamond and diamond like carbon coatings, to allow for effective and efficient dry turning of aluminium alloy Al 6082, has been investigated. Optimised diamond and diamond-like carbon (DLC) coatings were combined and deposited onto a WC-Co insert using chemical vapour deposition (CVD) methods. DLC coatings were developed by testing the effects of bias voltage, deposition time and gas pressure. During the development of the DLC layer, the effects of substrate geometry and positioning in the deposition chamber were investigated. It was discovered that coating characteristics could vary significantly across the samples as a result of geometrical effects. This contradicted claims that, as plasma enhanced CVD is a non-line of sight deposition method, any variation in the coating due to geometry would be negligible. SEM analysis revealed coating thickness to increase by over 50%. AFM measurements showed coating roughness to increase by up to 30 times, whilst Raman spectroscopy highlighted a significant decrease in sp3 bonding. This variation in characteristics was seen, through the use of scratch testing, to translate into significantly reduced tribological performance. Friction was increased by 60% and critical load was only half of that of the coating applied to flat surface. The combined coatings were characterised and machining performance was evaluated. Coating characteristics were examined using SEM, AFM and Raman spectroscopy. Cutting trials designed to simulate the expected tool life were conducted. Micro and nano-crystalline diamond coatings, with and without an additional DLC layer were trialled along with a single layer DLC coating. Commercially available uncoated and TiN coating inserts of identical geometry were also trialled as a reference. The results showed that the addition of the DLC layer effectively reduced the roughness of the diamond, however, this did not translate into reduced adhesion of the aluminium to the cutting tip. It has been shown that for this particular machining scenario, a smoother coating effectively increased friction and adhesion of the workpiece material. The investigation has highlighted that due to the complex dynamics of material transfer effects in sliding, it cannot be assumed that a smoother surface layer will lead to improved tribological performance.

Inconel 617 is a nickel-based superalloy whose properties include corrosion and oxidation resistance in high temperature environments. Due to their material properties, Inconel alloys are commonly used in aerospace applications where resistance to high pressure and temperature is required. These properties also cause the material to be hard to machine due to high temperatures in the cutting zone and its tendency to work harden. This paper focuses on improving the surface integrity and tool life for turning of Inconel 617 for use in next-generation nuclear applications. Various machining parameters are tested to improve the finish and tool life such as the feed rate, cutting speed, and depth of cut. While the machining of popular Inconel grades, such as Inconel 718, have been highly studied and understood, Inconel 617 lacks the knowledge base and research to define how the alloy behaves in machining and how it compares to other grades. Tests on tool coatings confirmed that commercially available coatings are durable enough to withstand the machining of this superalloy in finish turning and determined that AlTiN coatings provide the longest tool life. The investigations performed uncovered the relationship between cutting parameters and their influence on the surface integrity and tool life. MQL deposition was tested and found to be comparable and at times better than conventional flood coolant and may be considered a replacement for coolant after more improvement. This work details the knowledge and experimental procedure used to understand the machining of this superalloy. / Thesis / Master of Applied Science (MASc) / The purpose of this research is to develop an understanding of the machining of Inconel 617 for next-generation nuclear reactors. Canada’s plan to phase out coal-fired plants and deploy new nuclear reactors is contingent on being able to manufacture the necessary components. Inconel 617 is slated to be used in these high temperature, corrosive environments due to its high strength in elevated temperatures and its resistance to corrosion. However, since the material is a recent addition to the list of compatible materials, not much research has been performed on the manufacturing of this superalloy. Factors like cutting speed, coolant, and tooling were investigated and understood with the aim of improving the cost and time associated with manufacturing these nuclear grade components.

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This thesis deals with modern cutting cemented carbide tools. In the first section are stated several basic innovations already used tools for basic machining operations, which is turning, milling and drilling. It continues with analysis of single materials for production of cemented carbides, non coated as well as coated and with comparing of their properties. There are listed the basic cutting properties of the cutting tools after that. The penultimate point of the work is optimization of the basic machining operations, namely roughing and finishing, for a given application, which is in this case turning on the lamp stand. Finally, everything is summed up and evaluated in the conclusion.

Using of process liquids improves the procedure and results of machining, on the other hand, increases costs and raises some ecological and hygienic issues. In the work there is gradually analyzed mechanism of chip formation, progress and distribution of heat and thermal fields as well as economic and ecological aspects of dry machining and influence of dry machining on durability of tools. In the experimental part there are evaluated data which were measured during the drilling of cylindrical workpiece with regards to progress of workpiece thermal fields while using various kind of tool coating. In the final part there are stated recommendations for practice.

At the beginning of this diploma thesis I describe the production of different types of threads (with special emphasis on the production of internal threads), then I discuss different types of application of abrasion resistant coating by PVD and CVD, I describe their main advantages and disadvantages. Further, this diploma thesis explains particular mechanisms and forms of tool wear on tool with coating. In the second part of this diploma thesis the analysis of the current status of the production of internal threads in the Rail (high-pressure chamber) is made. In the last part I compare six different threads cutters by the use of a scanning electron microscope